Devil's Dyke

This is one of the four dyke's in East Anglia. It is Anglo-Saxon and runs for over seven miles, protecting the land between the fens and the wooded areas on the heavier land to the south east. Both the fens and the woodland were hard to navigate so the earthwork protected the vulnerable land between from the hoards and warmongers to the east.
Imagine digging that lot out with no 'diggers'. It is up to nine metres high!